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The majority of the basalt and gabbro samples dated to 250 million years ago, covered a surface area of 5,000,000 square kilometres (1,900,000 sq mi) on the Siberian Traps, [25] and occurred within a short period of time with rapid rock solidification and cooling. [26]
Debris flows with volumes ranging up to about 100,000 cubic meters occur frequently in mountainous regions worldwide. The largest prehistoric flows have had volumes exceeding 1 billion cubic meters (i.e., 1 cubic kilometer). As a result of their high sediment concentrations and mobility, debris flows can be very destructive.
The side displaying the bulb of force but without flake scars (barring an errailure flake scar or additional working of the flake) is called the ventral (or interior) surface, while the opposite side, displaying the flake scars of previous removals, or the cortical or original rock surface, is the dorsal (or exterior) surface.
Thousands of rocks that bear a strong resemblance to prehistoric tools have been found at the site, both on the surface, and up to 8 m (26 ft) below the surface. A stone from the Master Pit had been dated to over 200,000 BP. This date could have been the result of contamination from other elements in the soil, so currently there is an effort to ...
Today the bottom of Spirit Lake is 100 ft (30 m) above the original surface, and it has two and a half times more surface area than it did before the eruption. The largest known of all prehistoric landslides was an enormous submarine landslide that disintegrated 60,000 years ago and produced the longest flow of sand and mud yet documented on ...
The outermost ring was identified using seismic reflection data. It is up to 130 kilometers (81 mi) from the crater center, and is a ring of normal faults, throwing down towards the crater center, marking the outer limit of significant crustal deformation. This makes it one of the three largest impact structures on Earth.
The Espinaso Formation includes a wide variety of volcaniclastic materials. Volcaniclastics are geologic materials composed of broken fragments of volcanic rock. [1] These encompass all clastic volcanic materials, regardless of what process fragmented the rock, how it was subsequently transported, what environment it was deposited in, or whether nonvolcanic material is mingled with the ...
Debris flow deposits take the form of long, narrow tracks of very poorly sorted material. These may have natural levees at the sides of the tracks, and sometimes consist of lenses of rock fragments alternating with lenses of fine-grained earthy material. [20] Debris flows often form much of the upper slopes of alluvial fans. [22]